This invention relates generally to inkjet printing mechanisms, and in particular to techniques for maintaining inkjet printheads at its optimal conditions.
Inkjet printing mechanisms such as thermal inkjet printers and piezoelectric printers use pens which shoot drops of liquid colorant, referred to generally herein as xe2x80x9cink,xe2x80x9d onto a media sheet. Each pen has a printhead formed with very small nozzles through which the ink drops are fired. To print an image, each printhead is propelled back and forth across the media sheet, shooting drops of ink in a desired pattern as it moves. The particular ink ejection mechanism within the printhead may take on a variety of different forms known to those skilled in the art, such as those using piezoelectric or thermal printhead technology.
To clean and protect the printhead, typically a conventional xe2x80x9cwiping assemblyxe2x80x9d mechanism is mounted within the housing of the printing mechanism so the printheads can be moved to a wiping region over the assembly for maintenance, specifically for wiping off ink residue as well as any paper dust or other debris that has collected on the printheads. Normally, a printhead needs wiping after a certain amount of printing operations or a certain period of idleness.
For a printing mechanism having more than one printhead, all the printheads move to the wiping region together. Conventionally, several flexible wiper-blades in close proximity to each other are provided in the conventional wiper assembly to wipe all the printheads simultaneously.
However, different printheads may have different needs for maintenance due to different characteristics and usage during printing operations. The fact that one printhead needs wiping normally does not justify the wiping of the other printheads. If all the printheads are wiped at the same time whenever one of them needs wiping, the printheads may be exposed to excessive amount of wiping. Potentially, such excessive wiping of the printheads may deteriorate the health of the printheads.
Therefore, there is a need for an improved printhead wiping mechanism which optimizes the amount of wiping for different printheads.
According to an aspect of the present invention, in a method for independently wiping a first and a second printhead of an inkjet printing device, a first and a second wiping assembly separated from each other are provided in the printing mechanism. Furthermore, the wiping of the first printhead by the first wiper and the wiping of the second printhead by the second wiper are separately controlled.
According to a second aspect of the present invention, a method for wiping a first and a second printhead of an inkjet printing mechanism is provided. A first and a second wiper are movable to a wiping region in the printing mechanism and correspond to the first and second printheads respectively. Furthermore, each wiper is individually adjustable. During wiping operations, both printheads are moved to the wiping region facing the wipers. In addition, a character of the first wiper, that is, its position relative to its corresponding printhead, is adjusted prior to wiping of any printheads. Subsequently, both wipers are driven along a wiping axis such that the second printhead is wiped by the second wiper, with the first printhead not being simultaneously wiped by the first wiper due to this adjustment prior to the wiping operation.
According to a further aspect of the invention, an inkjet printing mechanism includes a chassis, a pair of printheads, a pair of wipers movable to a wiping region for wiping the printheads, and a carriage that transports both printheads to the wiping region facing the wipers. Each wiper corresponding to one of the printheads respectively, and each wiper is individually adjustable such that each printhead can be independently wiped with the other printhead not being simultaneously wiped by its corresponding wiper.
Other aspects and advantages of the invention will become apparent from the following detailed description in conjunction with the accompanying drawings; the description illustrates by way of example the principles of the invention.